Despite the danger on their doorstep, European leaders have lagged the United States in responding to Russian aggression in Ukraine. Until now, that is.

On Tuesday, the 28-nation European Union finally, and firmly, acknowledged the need for more muscular economic sanctions against Russia, even if they create newfound risks to E.U. member nations’ own sclerotic economies.

This laudable resolve is reflected in sanctions on some state-owned banks and restrictions on arms sales as well as technology and equipment for Russia’s oil industry.

After a teleconference on Monday with the leaders of the United Kingdom, France, Germany and Italy, the White House issued a statement stressing “the importance of coordinated sanctions measures on Russia for its continued transfer of arms, equipment and fighters into eastern Ukraine, including since the crash, and to press Russia to end its efforts to destabilize the country and instead choose a diplomatic path for resolving the crisis.”

“The crash,” of course, refers to the downing of Malaysia Airlines Flight 17, which the United Nations said on Monday may amount to a war crime. It was allegedly committed by separatists in eastern Ukraine, who are inspired, supported, armed and trained by Russia. Separatists were similarly enabled in Crimea, which Russia illegally annexed in March.

And now Russia is officially accused of breaking the Intermediate-range Nuclear Forces Treaty that was signed in 1987 by President Ronald Reagan and Soviet leader Mikhail Gorbachev. The treaty includes a ban on testing ground-launched cruise missiles capable of flying 300 to 3,400 miles. Russia allegedly broke the ban as far back as 2008.

‘TRULY PAINFUL’

“This is a very significant step — the first truly serious, painful sanctions on Russia. Putin has been relying that he could keep Europe hived off from the United States. This would be a blow to this tactic. … We thought we had established a peace in Europe that would last a long time, but that peace is very much in doubt. Russia is conducting a hybrid war against a country that did nothing to it on the basis of lies and a false doctrine.”

JOHN HERBST, former U.S. ambassador to Ukraine and director of the Atlantic Council’s Eurasia Center

The public airing of that accusation may have been timed to ratchet up pressure on Russia, as well as to put Russian President Vladimir Putin’s rogue behavior in context. Indeed, this crisis is not just a regional dispute along the Russia-Ukraine border. Rather, Putin’s autocratic, erratic behavior poses a direct threat to other Eastern and even Central European countries, as well as the overall post-Cold War order. And it doesn’t stop at continental borders, as evidenced by Russia’s protection of dictators like Syrian President Bashar Assad, who continues to kill his citizens at an appalling rate.

Hours after the E.U. announcement, Obama moved to mostly match the sanctions. Obama should also consider how best to enhance Europe’s energy security and Ukraine’s territorial security.

America’s energy revolution not only is a domestic game-changer, it can augment foreign policy, too. Expediting the ability to sell liquefied natural gas to Europe could be crucial in stiffening European resolve. And it could also signal to Putin that over time his trump card — energy — won’t erode Western unity.

The United States shouldn’t risk a military confrontation in eastern Ukraine. But Obama should strongly consider providing actionable intelligence to the Ukrainian government so it can end the rebellion. On Monday, the United Nations reported that 799 civilians had been killed and 2,155 wounded in clashes since mid-April and that 330 Ukrainian forces had been killed. (There were no estimates for rebel deaths.) U.S. intelligence can strengthen Ukraine’s military hand so the fighting, and the tragic toll, can stop.

Whether all of this is enough to change Putin’s cold calculus remains to be seen. Although he’s increasingly an international pariah, he’s popular at home, especially because of distortions disseminated by Russian media. If Flight 17 won’t convince Putin — Russia has ramped up its military involvement since the downed jet — money might. Or at least it could convince enough of Putin’s inner-ring supporters, as well as Russian citizens, that the aggression carries an unacceptable cost.

This won’t happen overnight. And it won’t happen at all if the West allows domestic economic and political concerns to soften the sanctions. U.S.-E.U. unity on confronting Russia has finally arrived. But unless it’s durable, it won’t contain Putin.